Fuel injection pressure compensating mechanism



c. w. MAY 2,982,278

FUEL INJECTION PRESSURE COMPENSATING MECHANISM May 2, 1961 Filed April 14, 1960 fnvenfar: fiarles Z. Ma. y mi United States Patent FUEL INJECTION PRESSURE COMPENSATING MECHANISM Charles W. May, Decatur, Ill., assignor to Borg-Wamer Corporation, Chicago, 111., a corporation of Illinois Filed Apr. 14, 1960, Ser. No. 22,321

Claims. (Cl. 123140) Thisinvention relates generally to fuel injection systems for internal combustion engines and more particularly to'means for varying the fuel delivered to the engine as a function of load requirements and ambient pressure or altitude requirements.

It is a general object of the presentinvention to provide an improved control system for a fuel injection pump which will respond to changes in engine load and ambient pressure in order that an optimum fuel to air ratio (F/A) be delivered for all conditions of engine operation.

It is another object to provide an improved control mechanism having an ambient pressure sensing device lcapable of sensing and translating changes in ambient pressure into a force effective to vary the fuel supply to the engine cylinders.

It is still another object of this invention to provide an improved mechanism for a fuel injection pump which is simultaneously responsive to the load requirements of the engine as sensed through manifold pressure and to ambient pressure through a bellows open to atmosphere, to vary the fuel supplied to the engine in accordance with engine requirements thereby providing optimum fuel plifying system and a repositioning means for causing changes in fuel delivered to theengine as required by changes in ambient pressure. g

It is a more specific object of the present invention to provide a control device operable to effect the delivery of a fuel injection pump which comprises means sensitive to engine load and ambient pressure, which include an ambient pressure sensitive bellows operable to energize an electricservomechanism which in turn immediately seek's and finds a new control orientation as required by ing mechanism showing the electrical connection panel and show with greater particularity the means interconnecting the sensing element and the switch.

Fig. 4 is a schematic drawing of the basic system showing the interrelation of the various parts.

Referring now to the drawings wherein like designating characters are embodied in the various views to identify like parts. In Fig. 1 of the drawings, a preferred embodiment of the present invention is generally indicated at 10, and is typically comprised of a load compensating section 12, an altitude or ambient pressure compensating section 13, and a translating and integrating section 11, the translating section being adapted to receive signals from the load compensating and altitude compensating sections, translate and integrate these signals, and transmit them as a single response to the fuel pump in order to vary the amount of fuel delivered to the internal combustion engine.

Referring first to the translation section 11, there is contained within a casing 14, a two-dimensional cam 15,

an ambient pressure compensating guide arm 16, and a cam follower and transmitting arm 17. The two-dimensional cam 15 has a predesigned cam surface 18 on one side thereof and a plurality of knuckles 19 opposite thereto. The compensating guide arm 16. is rotatable about a pivot point 20 (here shown as a screw) and hasa smooth, predesigned, surface 21 which serves as a track or guide upon which knuckles 18 of cam 15 slide. Transmitting arm 17 is rotatable about a pivot point 22, and is equipped with a roller cam follower 23 at an opposite end of the arm from the pivot 22. A socket 24 having a concave surface 25 is rotatably mounted on .a pin 26 at a predetermined distance between the roller 23 and the pivot 22. The socket 24 receives. a pump output control pin 27 in the concave portion 25 and acts against the pin 27 .so as to move it longitudinally for thereby varying the output of'the pump P. .The pin 27 is forced inwardly by resilient means (not shown) comprising a part of a pump P.

The load compensating section is housed within a casing 30 which is fixedly. attached by screws 31 to the casing 14 of the translationsection 11. A diaphragm 32, is secured between the casing 14 and 30, and effectively divides the load compensating section 12 into chambers 33 and 33a. Chamber 33 is in direct communication with the translation section 11 through, an opening 34, in the casing 14 an remains generally at atmospheric or ambient pressure at all times. (The translation and pressure compensating sections 11 and 13 are subject to atmospheric the new pressure condition, :and immediately conditions itself so as to be capable of pressure change. V V

The invention consists of the novel 'constructions, arrangements 'and devices to be hereinafter described and claimed for carryingout the above stated objects and responding to any subsequent 'such other objects aswill be apparent from the following ing a preferred arrangement cf-the elements comprising .-the, mechanism.

r Fig. Zia atop view of an;ambient' pressurgeornpensat preferred embodiment of the control mechanism of the present invention, showor ambientpressure at all times.) Chamber 33a is in direct communication through port C with the intake manifold M of the engine and is therefore maintained at manifold pressure at allitimesn A'pair of relatively stiff plates 35 and 35a are situated back to back on} either side" of the diaphragm -32 and are secured to each otherby some appropriate means. The diameters ofthe plates are relatively smaller than that of the-casing and housing 30 so as to allow the diaphragm freedom ofrnovement, laterally as seen in Fig. 1 withinthe housing 30. Plate 35 isentirely contained within' chamber- 33:; and serv 'es as a springjetainer for compressed spring 3e, which exerts V a eontinuing force to the right asseenin Fig. l, tending to force the diaphragm toward the translation sectionll.

.. A link 37Vis secured to plate 3 5a and extends transverse- ,l to the platelandjnt he translation mechanism throu gh opening134. The link .37 is afttaeheglby mean of. pin 38 to one endiofithe twmd iinensiona gam 1,5 7

manner that the cam 15 is free to rotate about the pivot pin 38. -j .7 T Pres nve ion, in it morespe ti aspeqt per.- t'ain's to the construction, arrangemenflani iope'rationpf the altitude or ambient, pressure compensating. mechanism 13 Within a casing 40, whichis' attachedto casing 14 by'any appropriatem'eans (not shown), thereis Contained a pressure sensin'gdevice41 such as an'jeX- pansible bellows, carrying two co-ajt'ial terminalsj41a and 41b. One. terminal 41a is secured to the casing 40 by appropriate 'm'eansls uch' as by a nut and bolt 42. The exterior of the bellows 41 is subject to atmosphere orambient pressureat all times A link 43 is secured to the other terminal 41b ofjthe bellows andfpass es through a guide opening 44in the casing 40.. The link :43 is free to move with the expansion and contraction ofthe bellows41; .7 v f A lever bar 45 is vprovided with pairs of bifurcated yoke defining arms 46 and 46a at "one end thereof, and '47 and 47a at the other end thereof. The arms 46 and 46a are attached to theend of link 43 by means of pin "48. A movable fulcrum v50 for the arm 45 is provided at a predetermined distance from pin 48.

v Fulcrum 50 is of a generally yoke shape and is threadably mounted upon a rotatable screw 51 which is "rotatably retained in bearing relation in casing 40. Fulcrum 50 is attached to the lever arm 45 by means of a ,pair' of pins 52. A slot 53-is'provided in lever arm 45 for allowing member 51 to pass therethrough. The arms 47 and 47a of the lever 45 are connected .by'means of 'a.pin55 to apivoted center post 57 of an electrical double throw or reversing switch 56.

, Switch 56 comprises thecenter post 57 which is electrically insulated from both casing 40 and lever arm 45, and a pair of fixed contact points 58 and 59 spaced adjacent the center post 57 .on eitherside thereof. The points 58 and 59 are also .electrically insulatedfrom the casing 40. The switch 56 is connected to an electrical .power source PS andto a reversible electric motor 60.

.The motor 60 is energized for one direction of rotation by the post 57 contacting the. point'58, and, for theother direction by the post l57. contacting the point 59. The electric motor 60 is secured in. casing 40..and has an output shaft 60a. The output shaft 60a..carries-a dr iv- ,ing gear 61. The gear 61 isintmesh' with a relatively ,larger gear 62 secured to one endv of .thescrew shaft 51, and to anoth er gearl 63 attached to a rotatable shaft A64, The shaft 64 is journalled in the casing 40 and passes through the yoke arms 47. and 4.7a of the. lever 45, and

-"through an opening 65 in casing 40 into the translating and integrating section 11.,

A common wall 66 separatesthe translating section -11 and the ambient pressure compensating section 13' and .has a protuberance or boss 67; formed with a threaded bore 68. A threaded shaft69 is contained within the bore 68 and is formed with an ,axial bore 70 therethrough. The shaft 69 also has a transve'rseslot71: formed'as ,by a saw cut. One end of the shaft '64' extends into the bore 70 and carries a transverse pin 72 which engages the slot 71. The shaft 64 also carries a frusto-conical shaped cam 73- having a surface 74 which contacts the compensating guidearm 16 at point 75. In operation, considerating'first the ambient pressure compensating section 13, bellows 41 expandsor contracts in response. to'chan'ges in ambient pressure. In so 4 doing, link 43 is moved to. they left or right thereby causing lever 45 to pivot on the fulcrum 50 and cause center .post.,57 to makeelectrical contact with either" contact point.58 or 59 depending upon which direction thefbellows 41 ,moves. ,Ascanibe seen from the" arrangement .of elements, aa'ex sionof the bellows 41, which would re ul ifdn gatd c ea g in.i ifiie itf n esw ("mo es f lever 45 "and forces the center" p'ost 57'into contact with point 58. Conversely, an increase in ambient pressure would cause center post 577to contact point 59.

For purposes of description, the power source PS may be a conventional automobile battery, and it may be assumed that the center post 57 is connected to the positive terminal thereof. As either one of the contact points 58 or 59 is touched by the center vpost 57, current flows through the motor 6 0,to ground, causing the motor 60 to rotate in a given direction. The post 57 contacting the other point causes the motor 60 to rotate in the opposite direction.

The motor 60 drives the gear 61 which in turn drives the gears 62 and 63, causing shafts 64 and 51 to rotate simultaneously. :As sh'aft 64 rotates, pin 72 causes shaft 69 to rotate and advance or retract the cam 73, depending on the direction of rotation. The speed at which the cam 73 moves is, of course,.a function of the pitch of the, threads and the 'speed of rotation of shaft 64 as transmitted to 'shaft 69; p 1 7 As shaft 51 rotates, the fulcrum 50 advances or retracts along the'screw'shaftSl, thereby moving the lever 45. The elements are so arranged that such movement of lever 45 is in a direction that causes the points to open, thus breaking the electrical circuit and causing the motor 60 to stop rotating. 'In'this manner, the lever 45 and switch 56 of the ambient pressure compensating section 13' is again in condition to respond to a subsequent change in pressure ,as sensed by the bellows 41.

In normal operation, the pressure changes encountered are gradual and varyin small increments. Itis contemplated, therefore, that the motor 60 will be energized infrequently and for only the small increments of time necessary to move the fulcrum 50 and lever 45 to compensate for the changes in pressure. During operation, at a fairly constant altitude, the only ambient pressure changes that may beencountered are barometric, and the motor 60 of the compensating mechanism 13 may be virtually inoperative. I

Special attention is directed to the co-action'of the motor driven cam 73 and movable fulcrum 50. In the preferred embodimentshown in Fig. 1, th e' fulcrum'and cam are interconnected by means of'gearing butjthis is by no means to be limiting upon the scope of the invention. The ambient pressure compensating section is-sodesigned thata change inambient pressure will energlze the motor 60 which, by means of a specific relation determined by the gear ratio 63:6l "and the threads formed on shaft 69, will cause apredetermined lateral movement of cam 72 per unit of pressure change. The fulcrum 50, which is mountedon the thread screws5l, is geared, in this embodiment, to-the motor 60.. The gear ratio 62:61 and the threads on screw 51 are so designed and so interrelated with the movement of the cam 72 that the fulcrum 50 will move in the desired direction and the desired amount to cause the switch 56to-be I opened at precisely the time when the cam 72 has moved the amount necessary to; compensate for the pressure change which stimulated'the mechanism. U

The load compensating mechanism 12 operates in a manner which is generally well known-in theart. As manifoldpressure inchamber 33a varies, the diaphragm 32 moves in accordancewith the unbalance of pressures until an equilibrium position is reached wherein the force due to pressure differential isbalanced by the-force of the spring36. The'equilibrium seeking movement-of thediaphragm 32 is transmitted by link 37 to the'twopressure 1 due to -increased altitude. In response to increased load, manifold prcssure increases thereby caus- 'ing' "an increased presstirein chamber 33:11 -"-'In seeking an equilibrium position. the diaphragm 32 moves to the right, or toward the transmission section 11, causing cam to slide upon track 21 of guide arm 16. The cam surface 18 acts on arm 17, forcing it downward thereby forcing control pin 27 downward.

By way of example it will be assumed that a downward movement of the control pin 27 causes the pump P to deliver a greater quantity of fuel, and an upward movement of the pin 27 will cause the opposite result.

Simultaneously, bellows 41 senses a decrease in atmospheric or ambient pressure. Accordingly, the bellows 41 expands in proportion to the change in pressure. This movement is transmitted by link 43 to lever 45 which in turn completes an electrical connection between center post 57 and contact point 58. Motor 60 begins to rotate--let us say, in the counter-clockwise direction. In so doing, shaft 64 and shaft 51 rotate in the opposite or clockwise direction in direct proportion to the relative numbers of teeth on the respective gears 62 and 63 in mesh with motor shaft 61. The gear ratio, in the embodiment illustrated, is such that the shaft 64 will ro tate relatively faster than the shaft 51.

Assuming a normal right hand thread on shaft 69, as shaft 64 rotate, the conical section 73 moves toward the right as seen in Fig. 1. Since the cam 73 has a decreasing diameter towards the left, its movement toward the right causes the guide arm 16 to turn counterclockwise about its pivot to new position.

Thus, guide arm 16 interprets a decrease in ambient pressure through the compensating mechanism ,13 and is repositioned or reoriented in the counter-clockwise direction a corresponding number of degrees. If the only change encountered were a decrease in ambient pressure, the resultant effect would be the before mentioned reorientation which would accordingly influence the cam 15 which is guided by arm 16 hereby changing the angle of cam surface 18-the result being an appropriate leaning of the mixture supplied to the engine, by an upward movement of control pin 27, which normally has an upward pressure on it at all times thereby maintaining its position in the guide 24. At the same time, shaft 51, which is being rotated at a relatively slower rate, causes translating and integrating means for controlling the output of said pump; engine load sensitive means interconnected with said traslating means and effective to modify the position of saidtranslating means in response to changes m engine load; and ambient pressure sensing means adapted to reorient said translating means in response to changes in ambient pressure; said ambient pressure sensing means including an expansible bellows sensitive to changes in ambient pressure, electric motor driven power amplifying means operatively interconnected with said bellows and adapted to be energized by the movements of said bellows, and means interconnecting said electric power amplifying means and said translating and integrating means operable to reorient saidtranslating and integrating means in response to changes in ambient pressure.

2. In a control mechanism for a fuel injection system for an internal combustion engine, the combination of a fuel injection pump for supplying fuel to the engine; translating and integrating means for controlling the output of said pump; engine load sensitive means interconnected with said translating means and effective to modify the position of said translating means in response to changes in engine load; and ambient pressure sensing means adapted to orient said translating means in response to changes in ambient pressure; said ambient pres- .sure sensing means including an expansible bellows sensitlVG to atmospheric pressure, an electric motor driven power amplifying means, motion transmitting means attached to said expansible bellows and adapted to transmit movements of said bellows so as to cause saidelectric motor driven power amplifying means to be energized,

fulcrum 50 to move to the left, thereby causing the electrical contact to be broken and the motor 60 to stop.

The switch 56 opens at the precise time when cam 72 has moved the predetermined amount according to the pressure change. The ambient pressure compensating mechanism is now in condition for the next movement of the bellows 41 in response to changes in ambient pressure.

When there are simultaneous changes in load and ambient pressure, both compensating mechanisms respond individually, their response being integrated in a corresponding repositioning of pin 27. Thus, as in the example, while the ambient pressurecompensating mechanism has caused'reorienting of guide arm 16 to give a leaner mixture; theincreased load causes the. load compensating mechanism 12 to move to the right as seen in Fig. l, causing cam 15 also tomove to the right which .effectivelycalls'for more fuel to be delivered. Thus, it is seen thatrthe separate responseof the various compensating mechanisms are translated and interpreted into a single response which effectively varies the fuel output of thejpump in order to provide optimum operating conditions. j V i While this invention has been describedin connection with" certain specific embodiments thereof, it is to be understood that is by way of illustration and not by way of limitation and'the scope of this invention is defined solely by the appendedclaims' which should be construed and means interconnected with and adapted to be moved by said electric motor driven power amplifying means 35 for reorienting said translating and integrating means in response to changes in atmospheric pressure, and repositioning means for conditioning said ambient pressure sensing means for subsequent changes in pressure.

3. In a control mechanism for a fuel injection system for an internal combustion engine, the combination of a fuel injection pump for supplying fuel to the engine; translating and integrating means for controlling the output of said pump; engine load sensitive means interconnected with said translating means and effective to modify the position of said translating means in response to changes in engine load; and ambient pressure sensing means adapted to orient said translating means in response to changes in ambient pressure; an electricmotor driven power amplifying means including a source of electric "power, a reversible electric motor, and a reversing switch 'motor and said power source, means defining an adjustable lever mechanism interconnecting said expansible bellows and said switch and adapted to cause said switch to complete said electrical circuit in response to the movements of said bellows, and means interconnecting said electric motor driven power amplifying means and said translating and integrating means for reorienting said translating and integrating means in response to changes in atmospheric pressure.

4. In a control mechanism for a fuel injection system for an internal combustion engine, the combination of a fuel injection pump for supplying fuel to the engine; translating and integrating means for controlling the output of said pump; engine load sensitive means interconnected with said translating means and effective to modify the position of said translating means in response to changes in engine load; and arnbient pressure sensing means adapted to orient said translating means in responseto changes in ambient pressure; said ambient pressure sensing means including an expansible bellowssensitive to atmospheric pressure, an electric motor driven power amplifying means, adjustable lever means including a movable fulcrum attached to said bellows and interconnected with said reversing switch includinga reversible electric motor and a reversing switch, and adapted to transmit the movements of said bellows to saidswitch for thereby completing said electric circuit and causing said motor to be energized, and means interconnected with and adapted to be moved by said electric motor driven power amplifying means for reorienting said translating and integrating means in response to changes in atmospheric pressure, and repositioning means for conditioning said ambient pressure sensing means for subsequent changes in pressure.

5. In a control mechanism for a fuel injection system for an internal combustion engine, the combination of a fuel injection pump for supplying fuel to the engine; translating and integrating means for controlling the output of said pump; engine load sensitive means'interconnected with said translating means and effective to modify the position of said translating means in response to changes in engine load; and ambient pressure sensing means adapted to reorient said translating means in response to changes in ambient pressure; an electric motor driven power amplifying means including a source of electric power, a reversible electric motor, and a reversing switch for completing an electric circuit between said electric motor and said power source, an adjustable mechanism attached to said bellows and interconnected with said reversing switch, a fulcrum attached to said lever for allowing said lever to pivot, for amplifying the movements of said bellows and thereby causing said switch to complete said electrical circuit and energize said'electric motor, said fulcrum also being movable transverse to said lever for repositioning said lever, and means interconnecting said electric motor driven power amplifying means and said translating and integrating means for reorienting said translating and integrating means in response to changes in atmospheric pressure. 7 v

6. In a control mechanism for a fuel injection system for an internal combustion engine, the combination of a fuel injection pump for supplying fuel to the engine; translating and integrating means for controlling the output of said pump; engine load sensitive means interconnected with said translating means and effective to modify theposition of said translating and integrating means in response to changes in engine load; and ambient pressure sensing means adapted to further modify said translating and integrating means in response to changes in ambient pressure; said ambient pressure sensing means including an expansible bellows sensitive to ambient pressure, an electric motor driven power amplifying means, including a source'ofelectric power, a reversible electric ymotor, and a reversing switch for completing an electrical circuit between said electric motor and said power source, a lever interconnecting said expansible bellows and said switch and adapted to cause said switch to complete said electrical circuit in response to movements of said bellows, and cam means contacting said translating and integrating means and interconnected with said electric motor driven power amplifying means and adapted to move said translating and integrating means in response to changes in ambient pressure. 7

v '7. A control mechanism as set forth in claim 6 whereamount in response to an increment of pressure change. 8. In a control mechanism for a fuel injection system for an internal combustion engine, the combination of a fuel injectionpump for supplying fuel to the engine; translating 'andintegrating means for controlling the out- 7 pressure.

aasaars put oflsaid pump;'engine load sensitive means interconfy the'position of saidtranslating and integrating means in response to changes in engine load; and ambient pressure sensing means adapted to reorient said translating and integrating means in response to changes in ambient pressure; said ambient pressure sensing means including an expansible bellows sensitive to ambient pressure, an electric motor driven power amplifying means, including a source of electric power, a reversible electric motor, and a reversing switch for completing an electrical circuit between said electric motor and said'power source, an adjustable lever mechanism attached to said bellows and interconnected with said switch, a fulcrum attached to said lever for allowing said lever to pivot thereon, saidfulcrum being transversely movable with respect to said lever, means interconnecting said fulcrum and said electric motor driven power amplifying means for causing said fulcrum to move in response to changes in atmospheric pressure for thereby causing said lever to be repositioned in order to open said electric circuit and de-energize said electric motor driven power amplifying means, cam means in contact with said translating and integrating means, and means interconnecting said cam means and said electric motor for moving said cam means to reposition said integrating and translating means in response to changes in ambient pressure.

9. A control mechanism as set forth in claim 8 where- .ina rotatable screw interconnects said cam means and said electric motor driven power amplifying means, said rotatable screw being adapted to be rotated by said electric motor for thereby causing said fulcrum to move a predetermined distance in a given direction in response to an increment of pressure change.

10. In a control mechanism for a fuel injection system for an internal combustion engine, the combination of a fuel injection pump for supplying fuel to the engine;

translating and integrating means for controlling the output ofJsaid pump; engine load sensitive means interconnected with said translating andintegrating means and effective to modify the position of said translating and integrating means in response to changes in engine load;

' and ambient pressure sensing means adapted to reorient said translating and integrating means in response to changes in ambient pressure; said ambient pressure sensing means including an expansible bellows sensitive to ambientpressure, an electric'motor driven power amplifying means including a source of electric power, a reversible electric motor, and a reversing switch'adapted to complete an electric circuit joining said electric power source and said electric motor, a lever'adapted to interconnect said expansible bellows and said switch, and attached to said expansible bellows at one end thereof,

'gized; and means interconnecting said fulcrum advancing means and said cam moving means for co-ordinating the relative movement of said cam and said fulcrum for thereby causing said cam means to'be moved a predeterminedamount in response to a change in ambient No references cited. 

